Prevalence of Ehrlichiosis in Dogs with Gastrointestinal Bleeding Signs and Meta-analysis of Causal Association

Background: Most of the canine monocytic ehrlichiosis (CME) cases are left undetected until they reach the chronic stage which is non-responsive to the treatment resulting in death associated with panleucopenia. Hence, diagnosis of clinical or subclinical CME is of paramount importance to prevent entering into the fatal chronic stage. Methods: Dogs (n=50) presented with haemorrhagic signs were subjected to microscopic examination and immunochromatography test. Positive cases were subjected to haemato-biochemical analysis, radiography, ultrasonography and computerized tomography. Meta-analysis of clinical variables was done to determine the causal association. Result: CME was observed in 22.0 per cent of cases by lateral flow assay (LFA) and 2.0 per cent by microscopic examination. Pathological changes were noticed in the liver, spleen, kidney, lungs, urinary bladder and intestine. A decrease (P less than 0.05) in haemoglobin level (8.66±1.59), increase (p less than 0.05) in white blood cell (21.87±5.2), monocyte count (8.5±1.06) and serum alkaline phosphatase level (151.33±48.12) and increase (p less than 0.01) in blood urea nitrogen (57.64±12.82) was observed. Melena (91.6%) was the predominant sign among positive cases. The sign- specific prevalence rate was high for epistaxis, circling/ joint pain (100.0%), emaciation (100.0%) and monocytosis (75.0%). The relative risk for the prevalence of CME was 5 to 6 times more in dogs with emaciation (95% CI, 2.26 to 12.18) and melena (95% CI, 0.73 to 6.71). High prevalence was observed in females (28.5%, p greater than 0.05), 4-6-year-old (45.0%, p greater than 0.05), pure breeds (100.0%, p less than 0.01) and recent tick infestation (31.2%, p greater than 0.05). Antibody-based test, imaging techniques, haemato-biochemical analysis and the causal association could be useful tools in identifying the persistent ehrlichial infection.